The Carlisle Ribbon Factory looks fantastic too! I am not sue what your style preferences are, but I can tell you not to limit your searching to TK. There are many great sites that will help you find venues. Many of the lower budget ones aren't listed here because the knot charges a higher fee to list vendors than other sites...not that I'm complaining about TK, but it is true!
Mkincaid FYI, the Capitol is actually charging a fee now. I can't remember - I think it's $250-500 plus the liability insurance. It's because they no longer have a security guard on staff and that basically pays to have someone there. Not expensive at all, but not free anymore.